Skill Thrill: Multiple LEDs

I know, I know. If there was a making version of Portlandia (MAKElandia?) it would include a skit called ‘Put an LED on it!’ because what better way make it jazzy than to make it light up? I get the allure – building a circuit that works is fun and satisfying, and there is a certain swagger that comes with the control of turning components on and off at your whim. So putting LEDs on projects is a lot of fun. We do it fairly regularly during electronics workshops and sometimes for special projects, like “hack-your-notebook” day or when we work with soft circuits. LEDs, as you may know, turn on only when the electricity has the correct polarity meaning when the current is flowing into the positive arm of the LED and out of the negative arm. Look at this LED:

It has two arms, one long and one short. The long one is the positive arm and needs to connect to the positive terminal of a battery, and similarly the negative arm must go to the negative terminal. When that circuit is established, the LED lights up.

So it’s easy to see how to light one LED. But what if you want a bunch of them? You could connect them all to the battery like this:

but that restricts where you can place LEDs in your project without using a million miles of wire. To get LEDs to work far away from the battery, I like to train them. No, not like an animal. I like to arrange them in train tracks that can go as far as you want. What really happens is that I build parallel circuits sitting on top of each other with each loop being a bit bigger than the last.

To do this, I make sure to orient all the LEDs so that the positive arms point to one side and the negative to the other. Then I wind the positive arms around a rail (in this case an unbent paperclip)

and then I add another rail for the negative arms

All that remains is to attach sufficient battery power. I used a little battery housing here, but there are lots of ways to make that connection.

What are some other ways you’ve hooked up multiple LEDs? I’ve heard tell of a few others. Conductive thread, copper tape, and conductive ink all come to mind. We’d love to see what you’ve come up with — send us a picture of your project! You can tag us on Twitter (@makeshoppgh) or Instagram (@makeshoppgh), or email us directly at makeshop@pittsburghkids.org